What transcripts could be released?

Republican Senate Judiciary Committee Chairman Chuck Grassley said the panel would start releasing "all witness interviews that we have done related to that meeting" right away and "get them out to the public for everyone to see".

His panel leads one of four Russia-related inquiries into Trump officials.

As well as the president's eldest son, the committee has interviewed other participants at the controversial Trump Tower meeting.

They include music promoter Rob Goldstone, Russian-American lobbyist Rinat Akhmetshin and Anatoli Samochornov, a translator for Russian lawyer Natalia Veselnitskaya.

Dianne Feinstein, the most senior Democrat on the committee, said she was "delighted" by Mr Grassley's decision.

Image copyrightEPAImage caption
Mr Grassley and Mrs Feinstein

Why is Trump Tower meeting significant?

When it was first revealed, Mr Trump Jr said he met Ms Veselnitskaya in June 2016 at his father's Manhattan skyscraper to discuss US adoptions of Russian children.

The meeting took place in the run-up to the November 2016 presidential election, and he later acknowledged attending the meeting because he had been promised information that would help defeat Democratic candidate Hillary Clinton.

It was later reported by several media outlets that President Trump has personally dictated the first misleading statement, claiming the meeting was to do with adoptions.